A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of making an assembly can include juxtaposing a top surface of a first electrically conductive element at a first surface of a first substrate with a top surface of a second electrically conductive element at a major surface of a second substrate. One of: the top surface of the first conductive element can be recessed below the first surface, or the top surface of the second conductive element can be recessed below the major surface. Electrically conductive nanoparticles can be disposed between the top surfaces of the first and second conductive elements. The conductive nanoparticles can have long dimensions smaller than 100 nanometers. The method can also include elevating a temperature at least at interfaces of the juxtaposed first and second conductive elements to a joining temperature at which the conductive nanoparticles can cause metallurgical joints to form between the juxtaposed first and second conductive elements.

A method of forming a semiconductor package is provided. The method includes forming a metallization stack over a semiconductor die. Polymer particles are mounted over the metallization stack. Each of the polymer particles is coated with a first bonding layer. A heat spreader lid is bonded with the semiconductor die by reflowing the first bonding layer. A composite thermal interface material (TIM) structure is formed between the heat spreader lid and the semiconductor die during the bonding. The composite TIM structure includes the first bonding layer and the polymer particles embedded in the first bonding layer.

A method of forming a semiconductor package is provided. The method includes forming a metallization stack over a semiconductor die. Polymer particles are mounted over the metallization stack. Each of the polymer particles is coated with a first bonding layer. A heat spreader lid is bonded with the semiconductor die by reflowing the first bonding layer. A composite thermal interface material (TIM) structure is formed between the heat spreader lid and the semiconductor die during the bonding. The composite TIM structure includes the first bonding layer and the polymer particles embedded in the first bonding layer.

This invention provides a high-yielding and high-density/ultra-fine pitch package for ultra-large-scale ICs and advanced ICs. The package includes a substrate and a semiconductor chip. The substrate has a passivation layer covering a first surface of the substrate, wherein a plurality of holes are formed in the passivation layer, and a plurality of solder balls respectively accommodated in the plurality of holes. The semiconductor chip has a first plurality of pads, wherein a plurality of copper pillar micro-bumps respectively extend from the first plurality of pads, and the plurality of copper pillar micro-bumps are respectively connected to the plurality of solder balls.

A semiconductor package may include a base, a first chip on the base, and first connection patterns that connect and couple the base and the first chip. The first chip may include a substrate, pad patterns on the substrate, a passivation layer on the substrate and having openings, and pillars on the substrate, the pad patterns include a first signal pad and a second signal pad, the first connection patterns are in contact with the pillars, the pillars include a first signal pillar in contact with the first signal pad and a second signal pillar in contact with the second signal pad, the openings in the passivation layer include a first opening having a sidewall facing a side surface of the first signal pillar and surrounding the side surface of the first signal pillar, and a second opening having a sidewall facing a side surface of the second signal pillar and surrounding the side surface of the second signal pillar, and a maximum width of the second opening is greater than a maximum width of the first opening.

A method of forming an integrated circuit package includes attaching a first die to an interposer. The interposer includes a first die connector and a second die connector on the interposer and a first dielectric layer covering at least one sidewall of the first die connector and at least one sidewall of the second die connector. The first die is coupled to the first die connector and to the first dielectric layer and the second die connector is exposed by the first die. The method further includes recessing the first dielectric layer to expose at least one sidewall of the second die connector and attaching a second die to the interposer, the second die being coupled to the second die connector.

A method of forming an integrated circuit package includes attaching a first die to an interposer. The interposer includes a first die connector and a second die connector on the interposer and a first dielectric layer covering at least one sidewall of the first die connector and at least one sidewall of the second die connector. The first die is coupled to the first die connector and to the first dielectric layer and the second die connector is exposed by the first die. The method further includes recessing the first dielectric layer to expose at least one sidewall of the second die connector and attaching a second die to the interposer, the second die being coupled to the second die connector.

Disclosed are examples of integrated circuit (IC) structures and techniques to fabricate IC structures. Each IC package may include a die (e.g., a flip-chip (FC) die) and one or more die interconnects to electrically couple the die to a substrate. The die interconnect may include a pillar, a wetting barrier on the pillar, and a solder cap on the wetting barrier. The wetting barrier may be wider than the pillar. The die interconnect may also include a low wetting layer formed on the wetting barrier.

Disclosed are examples of integrated circuit (IC) structures and techniques to fabricate IC structures. Each IC package may include a die (e.g., a flip-chip (FC) die) and one or more die interconnects to electrically couple the die to a substrate. The die interconnect may include a pillar, a wetting barrier on the pillar, and a solder cap on the wetting barrier. The wetting barrier may be wider than the pillar. The die interconnect may also include a low wetting layer formed on the wetting barrier.